Much work is presently being done to produce air swirl in combustion chambers of an internal combustion engine. Air swirl is desirable in combustion engines because it promotes combustion stability, i.e., providing limited cycle to cycle variations of the air/fuel mixture and the air velocity profile in the cylinder, especially in the region of the cylinder proximate to the spark plug. As a result, the cylinders operate under similar firing conditions during each firing cycle especially at light load, or low torque output. This combustion stability allows a reduction in the lean operating limit of the internal combustion engine.
Prior to the present invention, efforts to produce air swirl have focused on redesigning the contour of the intake valve port opening into the combustion chamber by bringing the intake port closer to the engine block and forming a corkscrew shaped air intake path to the combustion chamber. Such efforts have proved disadvantageous because the opening of the intake valve port is fixed limiting the volume of air into the combustion chamber. As a result, the volume of air entering the combustion chamber during high RPM operation is less than that required to achieve maximum power output. This effect is known as reduced volumetric efficiency.
It is therefore a primary object of the present invention to provide a device for attaining high level combustion stability by producing a consistent air/fuel ratio and air swirl velocity profile in the cylinder, especially in the vicinity of the firing region of the spark plug, and especially under light load conditions by directing an air swirl int the combustion chamber of an internal combustion engine
It is a further object of the present invention to provide means for obtaining increased peak power output during high RPM operating conditions without increasing engine displacement by increasing volumetric efficiency and thereby generating the desired air flow into the cylinders during both light and heavy load conditions.
It is another object of the present invention to facilitate air-fuel preparation by providing a high speed swirl of air in the path of the fuel supplied by the fuel injector thereby placing fewer design constraints upon the fuel injector.